[Q] Mate 7 Strange Problem

Hello
I buy a huwaei ascend mate 7 two or three months ago.
after someday i notice that phone goes to a mode with gray background that shows a viewpager with one clock and musicplayer on each page and the phone doesn't allow to do anything else. there is no button to exit this mode, after reset or full wipe the phone stay in this mode too.
even after flash the official firmware the phone stay on this mode.
in this mode mobile rings and i can answer calls, but i can call to anyone, and cant do anything but play music and see the watch.

at first this happen one time in a day and handset goes off this mode quickly, but now in a day just two or three hours the phone is available.
the phone randomly goes off this mode and then get back to that.

anybody have any idea about this problem?

thanks